freedombone/src/freedombone-base-email

#!/bin/bash
#
# .---.                  .              .
# |                      |              |
# |--- .--. .-.  .-.  .-.|  .-. .--.--. |.-.  .-. .--.  .-.
# |    |   (.-' (.-' (   | (   )|  |  | |   )(   )|  | (.-'
# '    '     --'  --'  -' -  -' '  '   -' -'   -' '   -  --'
#
#                    Freedom in the Cloud
#
# Email functions
#
# License
# =======
#
# Copyright (C) 2014-2018 Bob Mottram <bob@freedombone.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# the default email address
MY_EMAIL_ADDRESS=$MY_USERNAME@$DEFAULT_DOMAIN_NAME

# When sending mail to riseup.net route to this onion address
RISEUP_EMAIL_ONION='wy6zk3pmcwiyhiao.onion'

# If you want to run a public mailing list specify its name here.
# There should be no spaces in the name
PUBLIC_MAILING_LIST=
# Optional different domain name for the public mailing list
PUBLIC_MAILING_LIST_DOMAIN_NAME=
# Directory where the public mailing list data is stored
PUBLIC_MAILING_LIST_DIRECTORY="/var/spool/mlmmj"

# If you want to run an encrypted mailing list specify its name here.
# There should be no spaces in the name
PRIVATE_MAILING_LIST=

GPG_KEYSERVER="hkp://keys.gnupg.net"

# whether to encrypt all incoming email with your public key
GPG_ENCRYPT_STORED_EMAIL="yes"

# optionally you can provide your exported GPG key pair here
# Note that the private key file will be deleted after use
# If these are unspecified then a new GPG key will be created
MY_GPG_PUBLIC_KEY=
MY_GPG_PRIVATE_KEY=

# optionally specify your public key ID
MY_GPG_PUBLIC_KEY_ID=

# automatic archiving of email
CLEANUP_MAILDIR_REPO="https://github.com/bashrc/cleanup-maildir"
CLEANUP_MAILDIR_COMMIT='33241d2e3861f901ba17f5c77ada007e1ec06a86'

# email encryption at rest
GPGIT_REPO="https://gitlab.com/mikecardwell/gpgit"
GPGIT_COMMIT='583dc76119f19420f8a33f606744faa7c8922738'

# refresh gpg keys every few hours
REFRESH_GPG_KEYS_HOURS=2

exim_version='4.89'

function rebuild_exim_with_socks {
    exim_socks_installed=$(get_completion_param "exim_socks")
    if [[ "$exim_socks_installed" == 'true' ]]; then
        return
    fi

    # shellcheck disable=SC2154
    if [ ! -d "$INSTALL_DIR/exim4" ]; then
        mkdir -p "$INSTALL_DIR/exim4"
    fi
    cd "$INSTALL_DIR/exim4" || exit 3468356
    rm -rf "$INSTALL_DIR/exim4/"*
    apt-get -qy install build-essential fakeroot devscripts
    apt-get source exim4-daemon-heavy
    apt-get -qy build-dep exim4-daemon-heavy
    cd "${INSTALL_DIR}/exim4/exim4-${exim_version}" || exit 356835685

    { echo 'Description: Socks proxying';
      echo ' Support for socks proxying of outgoing mail';
      echo ' This is to support onion email addresses, which require support for SOCKS5';
      echo ' .';
      echo " exim4 (${exim_version}-2+deb9u3) stretch-security; urgency=high";
      echo ' .';
      echo '   * Non-maintainer upload by the Security Team.';
      echo '   * Fix base64d() buffer size (CVE-2018-6789) (Closes: #890000)';
      echo 'Author: Salvatore Bonaccorso <carnil@debian.org>';
      echo 'Bug-Debian: https://bugs.debian.org/890000';
      echo '';
      echo '---';
      echo 'The information above should follow the Patch Tagging Guidelines, please';
      echo 'checkout http://dep.debian.net/deps/dep3/ to learn about the format. Here';
      echo 'are templates for supplementary fields that you might want to add:';
      echo '';
      echo 'Origin: <vendor|upstream|other>, <url of original patch>';
      echo 'Bug: <url in upstream bugtracker>';
      echo 'Bug-Debian: https://bugs.debian.org/<bugnumber>';
      echo 'Bug-Ubuntu: https://launchpad.net/bugs/<bugnumber>';
      echo 'Forwarded: <no|not-needed|url proving that it has been forwarded>';
      echo 'Reviewed-By: <name and email of someone who approved the patch>';
      echo "Last-Update: $(date +%Y-%m-%d)";
      echo '';
      echo '--- /dev/null';
      echo "+++ exim4-${exim_version}/Local/Makefile";
      echo '@@ -0,0 +1,32 @@';
      echo '+BIN_DIRECTORY=/usr/exim/bin';
      echo '+CONFIGURE_FILE=/usr/exim/configure';
      echo '+EXIM_USER=';
      echo '+SPOOL_DIRECTORY=/var/spool/exim';
      echo '+ROUTER_ACCEPT=yes';
      echo '+ROUTER_DNSLOOKUP=yes';
      echo '+ROUTER_IPLITERAL=yes';
      echo '+ROUTER_MANUALROUTE=yes';
      echo '+ROUTER_QUERYPROGRAM=yes';
      echo '+ROUTER_REDIRECT=yes';
      echo '+TRANSPORT_APPENDFILE=yes';
      echo '+TRANSPORT_AUTOREPLY=yes';
      echo '+TRANSPORT_PIPE=yes';
      echo '+TRANSPORT_SMTP=yes';
      echo '+LOOKUP_DBM=yes';
      echo '+LOOKUP_LSEARCH=yes';
      echo '+LOOKUP_DNSDB=yes';
      echo '+PCRE_CONFIG=yes';
      echo '+EXIM_MONITOR=eximon.bin';
      echo '+FIXED_NEVER_USERS=root';
      echo '+HEADERS_CHARSET="ISO-8859-1"';
      echo '+DLOPEN_LOCAL_SCAN=yes';
      echo '+LDFLAGS += -rdynamic';
      echo '+CFLAGS += -fvisibility=hidden';
      echo '+SYSLOG_LOG_PID=yes';
      echo '+EXICYCLOG_MAX=10';
      echo '+COMPRESS_COMMAND=/usr/bin/gzip';
      echo '+COMPRESS_SUFFIX=gz';
      echo '+ZCAT_COMMAND=/usr/bin/zcat';
      echo '+SUPPORT_SOCKS=yes';
      echo '+SYSTEM_ALIASES_FILE=/etc/aliases';
      echo '+EXIM_TMPDIR="/tmp"'; } > debian/patches/SOCKS

    debuild -us -uc
    cd "$INSTALL_DIR/exim4" || exit 3468356
    mv exim4_${exim_version}-*.deb exim4_${exim_version}_all.deb
    if [ ! -f exim4_${exim_version}_all.deb ]; then
        ls -l "$INSTALL_DIR/exim4/exim4_"*.deb
        echo "exim4_${exim_version}_all.deb not found"
        exit 63857368
    fi
    apt-mark -q unhold exim4
    dpkg -i exim4_${exim_version}_all.deb
    apt-mark -q hold exim4
    apt-get -yq remove --purge at

    systemctl restart exim4
    if [[ $(systemctl is-active exim4) != 'active' ]]; then
        apt-mark -q unhold exim4
        apt-get -yq install exim4 --reinstall
        systemctl restart exim4
    fi

    rm -rf "$INSTALL_DIR/exim4"

    set_completion_param "exim_socks" "true"
}

function email_create_template {
    if [ ! -d /etc/skel/log ]; then
        mkdir -m 700 /etc/skel/log
    fi
    if [ ! -d /etc/skel/Maildir ]; then
        mkdir -m 700 /etc/skel/.mutt
        mkdir -m 700 /etc/skel/Maildir
        mkdir -m 700 /etc/skel/Maildir/new
        mkdir -m 700 /etc/skel/Maildir/cur
        mkdir -m 700 /etc/skel/Maildir/Sent
        mkdir -m 700 /etc/skel/Maildir/Sent/tmp
        mkdir -m 700 /etc/skel/Maildir/Sent/cur
        mkdir -m 700 /etc/skel/Maildir/Sent/new
        mkdir -m 700 /etc/skel/Maildir/.learn-spam
        mkdir -m 700 /etc/skel/Maildir/.learn-spam/cur
        mkdir -m 700 /etc/skel/Maildir/.learn-spam/new
        mkdir -m 700 /etc/skel/Maildir/.learn-spam/tmp
        mkdir -m 700 /etc/skel/Maildir/.learn-ham
        mkdir -m 700 /etc/skel/Maildir/.learn-ham/cur
        mkdir -m 700 /etc/skel/Maildir/.learn-ham/new
        mkdir -m 700 /etc/skel/Maildir/.learn-ham/tmp
        ln -s /etc/skel/Maildir/.learn-spam /etc/skel/Maildir/spam
        ln -s /etc/skel/Maildir/.learn-ham /etc/skel/Maildir/ham
    fi

    if [ ! -d "/home/$MY_USERNAME/Maildir" ]; then
        mkdir -m 700 "/home/$MY_USERNAME/.mutt"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/cur"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/tmp"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/new"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/Sent"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/Sent/cur"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/Sent/tmp"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/Sent/new"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/.learn-spam"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/.learn-spam/cur"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/.learn-spam/new"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/.learn-spam/tmp"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/.learn-ham"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/.learn-ham/cur"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/.learn-ham/new"
        mkdir -m 700 "/home/$MY_USERNAME/Maildir/.learn-ham/tmp"
        ln -s "/home/$MY_USERNAME/Maildir/.learn-spam" "/home/$MY_USERNAME/Maildir/spam"
        ln -s "/home/$MY_USERNAME/Maildir/.learn-ham" "/home/$MY_USERNAME/Maildir/ham"
        chown -R "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/Maildir"
    fi
}

function create_email_onion_address {
    email_hostname='/var/lib/tor/hidden_service_email/hostname'
    if ! grep -q "hidden_service_email" /etc/tor/torrc; then
        { echo 'HiddenServiceDir /var/lib/tor/hidden_service_email/';
          echo 'HiddenServiceVersion 3';
          echo 'HiddenServicePort 25 127.0.0.1:25';
          echo 'HiddenServicePort 587 127.0.0.1:587';
          echo 'HiddenServicePort 465 127.0.0.1:465'; } >> /etc/tor/torrc

        function_check onion_update
        onion_update

        function_check wait_for_onion_service
        wait_for_onion_service email

        if [ ! -f $email_hostname ]; then
            echo $"email onion site hostname not found"
            systemctl restart tor
            exit 782352
        fi

        onion_address=$(cat $email_hostname)
        set_completion_param "email onion domain" "${onion_address}"
        add_email_hostname "$onion_address"
    else
        onion_address=$(cat $email_hostname)
    fi
    cp $email_hostname /etc/skel/.email_onion_domain
    cp $email_hostname "/home/$MY_USERNAME/.email_onion_domain"
    chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/.email_onion_domain"
}

function configure_email_onion {
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    if [[ "$SYSTEM_TYPE" == "mesh"* ]]; then
        return
    fi

    create_email_onion_address

    apt-get -yq install perl

    # MX record should be:
    # _onion-mx._tcp
    # 20:$onion_address
    # 3600 IN SRV 0 5 25 $onion_address

    # To test the system, on receiving server:
    #   exim -bd -d -oX 25
    # On the sensing server:
    #   exim -d -oX 25 -bt username@$onion_address

    { echo "perl_startup = do '/etc/exim4/perl-routines.pl'";
      echo "perl_at_start"; } > /etc/exim4/conf.d/main/00_exim4-config_perl

    { echo "use Net::DNS::Resolver;";
      echo "sub onionLookup {";
      echo "  my \$hostname = shift;";
      echo "  my \$res = Net::DNS::Resolver->new(nameservers => [qw(127.0.0.1)],);";
      echo "  \$res->port(5300);";
      echo "  my \$query = \$res->search(\$hostname);";
      echo "  foreach my \$rr (\$query->answer) {";
      echo "    next unless \$rr->type eq \"A\";";
      echo "    return \$rr->address;";
      echo "  }";
      echo "  return 'no_such_host';";
      echo "}"; } > /etc/exim4/perl-routines.pl

    { echo "riseup:";
      echo "  driver    = manualroute";
      echo "  domains   = riseup.net";
      echo "  transport = onion_relay";
      echo "  headers_remove = Received:Message-ID:X-Mailer:User-Agent";
      echo "  headers_add = Message-ID: <\${lc:\${sha1:\$message_id}}@\$sender_address_domain>";
      echo "  route_data = \${perl{onionLookup}{$RISEUP_EMAIL_ONION}}"
      echo "  no_more"; } > /etc/exim4/conf.d/router/905_exim4-config-riseup

    if ! grep -q "*.onion" /etc/exim4/conf.d/router/200_exim4-config_primary; then
       sed -i 's|domains = ! +local_domains|domains = ! +local_domains : ! *.onion : ! riseup.net|g' /etc/exim4/conf.d/router/200_exim4-config_primary
    fi

    { echo "onionrelays:";
      echo "  driver    = manualroute";
      echo "  domains   = *.onion";
      echo "  transport = onion_relay";
      echo "  headers_remove = Received:Message-ID:X-Mailer:User-Agent";
      echo "  headers_add = Message-ID: <\${lc:\${sha1:\$message_id}}@\$sender_address_domain>";
      echo "  route_data = \${perl{onionLookup}{\$domain}}"
      echo "  no_more"; } > /etc/exim4/conf.d/router/910_exim4-config-onionrelays

    { echo "onion_relay:";
      echo "  driver = smtp";
      echo "  helo_data = \"\$address_data \$original_domain\"";
      echo "  hosts_avoid_tls = *";
      echo "  socks_proxy = 127.0.0.1 port=9050"; } > /etc/exim4/conf.d/transport/050_exim4-config_onion_relay

    if ! grep -q "AutomapHostsOnResolve" /etc/tor/torrc; then
        echo 'AutomapHostsOnResolve 1' >> /etc/tor/torrc
    else
        sed -i 's|#AutomapHostsOnResolve.*|AutomapHostsOnResolve 1|g' /etc/tor/torrc
        sed -i 's|AutomapHostsOnResolve.*|AutomapHostsOnResolve 1|g' /etc/tor/torrc
    fi

    if ! grep -q "DNSPort " /etc/tor/torrc; then
        echo 'DNSPort 5300' >> /etc/tor/torrc
    else
        sed -i 's|#DNSPort .*|DNSPort 5300|g' /etc/tor/torrc
        sed -i 's|DNSPort .*|DNSPort 5300|g' /etc/tor/torrc
    fi

    if ! grep -q "DNSListenAddress" /etc/tor/torrc; then
        echo 'DNSListenAddress 127.0.0.1' >> /etc/tor/torrc
    else
        sed -i 's|#DNSListenAddress.*|DNSListenAddress 127.0.0.1|g' /etc/tor/torrc
        sed -i 's|DNSListenAddress.*|DNSListenAddress 127.0.0.1|g' /etc/tor/torrc
    fi

    update-exim4.conf.template -r
    update-exim4.conf
    dpkg-reconfigure --frontend noninteractive exim4-config
    systemctl restart tor
    systemctl restart exim4

    mark_completed "${FUNCNAME[0]}"
}

function check_email_address_exists {
    read_config_param ONION_ONLY
    read_config_param MY_USERNAME
    read_config_param DEFAULT_DOMAIN_NAME
    read_config_param MY_EMAIL_ADDRESS
    read_config_param DH_KEYLENGTH

    if [ ! "$MY_USERNAME" ]; then
        echo $'No username for email installation'
        exit 73672
    fi
    if [ ! "$DEFAULT_DOMAIN_NAME" ]; then
        echo $'No default domain name for email installation'
        exit 57634
    fi

    my_email="$MY_EMAIL_ADDRESS"
    if [ ${#my_email} -lt 3 ]; then
        MY_EMAIL_ADDRESS="${MY_USERNAME}@${DEFAULT_DOMAIN_NAME}"
        write_config_param "MY_EMAIL_ADDRESS" "$MY_EMAIL_ADDRESS"
    fi

    if [[ $ONION_ONLY != 'no' ]]; then
        my_email=$onion_address
        MY_EMAIL_ADDRESS="${MY_USERNAME}@$onion_address"
        write_config_param "MY_EMAIL_ADDRESS" "$MY_EMAIL_ADDRESS"
    fi
}

function backup_email {
    echo ''
}

function configure_firewall_for_email {
    if [[ "$INSTALLED_WITHIN_DOCKER" == "yes" ]]; then
        # docker does its own firewalling
        return
    fi
    if [[ "$ONION_ONLY" != "no" ]]; then
        return
    fi

    firewall_add Email 25 tcp
    firewall_add Email 587 tcp
    firewall_add Email 465 tcp
    firewall_add Imap 993 tcp
}

function encrypt_incoming_email {
    # encrypts incoming mail using your GPG public key
    # so even if an attacker gains access to the data at rest they still need
    # to know your GPG key password to be able to read anything
    if [ ! -d /etc/exim4 ]; then
        return
    fi

    # update to the next commit
    function_check set_repo_commit
    set_repo_commit "$INSTALL_DIR/gpgit" "gpgit commit" "$GPGIT_COMMIT" "$GPGIT_REPO"

    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi

    if [[ "$GPG_ENCRYPT_STORED_EMAIL" != "yes" ]]; then
        return
    fi

    if [ ! -f /usr/bin/gpgit.pl ]; then
        apt-get -yq install git libmail-gnupg-perl
        cd "$INSTALL_DIR" || exit 246824624
        function_check git_clone
        git_clone "$GPGIT_REPO" "$INSTALL_DIR/gpgit"
        cd "$INSTALL_DIR/gpgit" || exit 7246725474
        git checkout "$GPGIT_COMMIT" -b "$GPGIT_COMMIT"
        set_completion_param "gpgit commit" "$GPGIT_COMMIT"
        cp gpgit.pl /usr/bin
    fi

    # add a procmail rule
    if ! grep -q "/usr/bin/gpgit.pl" "/home/$MY_USERNAME/.procmailrc"; then
        { echo '';
          echo ':0 f';
          echo "| /usr/bin/gpgit.pl --encrypt-mode prefer-inline --inline-flatten $MY_EMAIL_ADDRESS"; } >> "/home/$MY_USERNAME/.procmailrc"
        chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/.procmailrc"
        { echo '';
          echo ':0 f';
          echo -n "| /usr/bin/gpgit.pl --encrypt-mode prefer-inline --inline-flatten \$USER@";
          echo "$DEFAULT_DOMAIN_NAME"; } >> /etc/skel/.procmailrc
    fi
    mark_completed "${FUNCNAME[0]}"
}

function encrypt_outgoing_email {
    # encrypts outgoing mail using your GPG public key
    # so even if an attacker gains access to the data at rest they still need
    # to know your GPG key password to be able to read sent mail
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    if [[ "$GPG_ENCRYPT_STORED_EMAIL" != "yes" ]]; then
        return
    fi

    if [ ! -d "/home/$MY_USERNAME/.gnupg" ]; then
        return
    fi

    if [ ! -f "/home/$MY_USERNAME/.muttrc" ]; then
        return
    fi

    # obtain your public key ID
    if [ ! "$MY_GPG_PUBLIC_KEY_ID" ]; then
        MY_GPG_PUBLIC_KEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        if [ ! "$MY_GPG_PUBLIC_KEY_ID" ]; then
            return
        fi
        if [ ${#MY_GPG_PUBLIC_KEY_ID} -lt 4 ]; then
            return
        fi
    fi

    if ! grep -q "pgp_encrypt_only_command" "/home/$MY_USERNAME/.muttrc"; then
        { echo '';
        echo $'# Encrypt items in the Sent folder';
        echo "set pgp_encrypt_only_command=\"/usr/lib/mutt/pgpewrap gpg --batch --quiet --no-verbose --output - --encrypt --textmode --armor --trust-model always --encrypt-to $MY_GPG_PUBLIC_KEY_ID -- -r %r -- %f\""; } >> "/home/$MY_USERNAME/.muttrc"
    else
        sed -i "s|set pgp_encrypt_only_command.*|set pgp_encrypt_only_command=\"/usr/lib/mutt/pgpewrap gpg --batch --quiet --no-verbose --output - --encrypt --textmode --armor --trust-model always --encrypt-to $MY_GPG_PUBLIC_KEY_ID -- -r %r -- %f\"|g" "/home/$MY_USERNAME/.muttrc"
    fi

    if ! grep -q "pgp_encrypt_sign_command" "/home/$MY_USERNAME/.muttrc"; then
        echo "set pgp_encrypt_sign_command=\"/usr/lib/mutt/pgpewrap gpg %?p?--passphrase-fd 0? --batch --quiet --no-verbose --textmode --output - --encrypt --sign %?a?-u %a? --armor --trust-model always --encrypt-to $MY_GPG_PUBLIC_KEY_ID -- -r %r -- %f\"" >> "/home/$MY_USERNAME/.muttrc"
    else
        sed -i "s|set pgp_encrypt_sign_command.*|set pgp_encrypt_sign_command=\"/usr/lib/mutt/pgpewrap gpg %?p?--passphrase-fd 0? --batch --quiet --no-verbose --textmode --output - --encrypt --sign %?a?-u %a? --armor --trust-model always --encrypt-to $MY_GPG_PUBLIC_KEY_ID -- -r %r -- %f\"|g" "/home/$MY_USERNAME/.muttrc"
    fi

    mark_completed "${FUNCNAME[0]}"
}

function encrypt_all_email {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ "$GPG_ENCRYPT_STORED_EMAIL" != "yes" ]]; then
        return
    fi

    if [ -f "/usr/local/bin/${PROJECT_NAME}-encrypt-mail" ]; then
        if [ ! -f /usr/bin/encmaildir ]; then
            cp "/usr/local/bin/${PROJECT_NAME}-encrypt-mail" /usr/bin/encmaildir
        else
            HASH1=$(sha256sum "/usr/local/bin/${PROJECT_NAME}-encrypt-mail" | awk -F ' ' '{print $1}')
            HASH2=$(sha256sum /usr/bin/encmaildir | awk -F ' ' '{print $1}')
            if [[ "$HASH1" != "$HASH2" ]]; then
                cp "/usr/local/bin/${PROJECT_NAME}-encrypt-mail" /usr/bin/encmaildir
            fi
        fi
    else
        if [ ! -f /usr/bin/encmaildir ]; then
            cp "/usr/bin/${PROJECT_NAME}-encrypt-mail" /usr/bin/encmaildir
        else
            HASH1=$(sha256sum "/usr/bin/${PROJECT_NAME}-encrypt-mail" | awk -F ' ' '{print $1}')
            HASH2=$(sha256sum /usr/bin/encmaildir | awk -F ' ' '{print $1}')
            if [[ "$HASH1" != "$HASH2" ]]; then
                cp "/usr/bin/${PROJECT_NAME}-encrypt-mail" /usr/bin/encmaildir
            fi
        fi
    fi

    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi

    if [ ! -f "/home/$MY_USERNAME/README" ]; then
        touch "/home/$MY_USERNAME/README"
    fi
    if ! grep -q $"If you have imported legacy email which is not encrypted" "/home/$MY_USERNAME/README"; then
        { echo '';
          echo '';
          echo $'# Encrypting legacy email';
          echo $'If you have imported legacy email which is not encrypted';
          echo $'then it can be encrypted with the command:';
          echo '';
          echo '  encmaildir';
          echo '';
          echo $'But be warned that depending upon how much email you have';
          echo $'this could take a seriously LONG time on the Beaglebone';
          echo $'and may be better done on a faster machine.'; } >> "/home/$MY_USERNAME/README"
        chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/README"
        chmod 600 "/home/$MY_USERNAME/README"
    fi

    mark_completed "${FUNCNAME[0]}"
}

function email_client {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    apt-get -yq install lynx abook urlview mutt

    if [ ! -f /etc/Muttrc ]; then
        echo $"ERROR: Mutt does not appear to have installed. $CHECK_MESSAGE"
        exit 49
    fi

    if [ ! -d "/home/$MY_USERNAME/.mutt" ]; then
        mkdir "/home/$MY_USERNAME/.mutt"
    fi
    echo "text/html; lynx -dump -width=78 -nolist %s | sed ‘s/^ //’; copiousoutput; needsterminal; nametemplate=%s.html" > "/home/$MY_USERNAME/.mutt/mailcap"
    cp "/home/$MY_USERNAME/.mutt/mailcap" /etc/skel/.mutt
    chown -R "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/.mutt"
    chown -R root:root /etc/skel/.mutt

    { echo 'set mbox_type=Maildir';
      echo 'set folder="~/Maildir"';
      echo 'set mask="!^\\.[^.]"';
      echo 'set mbox="~/Maildir"';
      echo 'set record="+Sent"';
      echo 'set postponed="+Drafts"';
      echo 'set trash="+Trash"';
      echo 'set spoolfile="~/Maildir"';
      echo 'auto_view text/x-vcard text/html text/enriched';
      echo 'set header_cache="+.cache"';
      echo 'set markers=no';
      echo '';
      echo '# ctrl-u to view long URLs';
      echo 'macro pager \cu <pipe-entry>"urlview"<enter> "Follow links with urlview"';
      echo '';
      echo 'macro index S "<tag-prefix><decode-save>=.learn-spam<enter>" "move to learn-spam"';
      echo 'macro pager S "<decode-save>=.learn-spam<enter>" "move to learn-spam"';
      echo 'macro index H "<tag-prefix><decode-copy>=.learn-ham<enter>" "copy to learn-ham"';
      echo 'macro pager H "<decode-copy>=.learn-ham<enter>" "copy to learn-ham"';
      echo '';
      echo '# set up the sidebar';
      echo 'set sidebar_width=22';
      echo 'set sidebar_visible=yes';
      echo '';
      echo 'set rfc2047_parameters';
      echo '';
      echo '# Show inbox and sent items';
      echo 'mailboxes = =admin =Sent =maybe-spam =spam';
      echo '';
      echo '# Alter these colours as needed for maximum bling';
      echo 'color sidebar_new yellow default';
      echo 'color normal white default';
      echo 'color hdrdefault brightcyan default';
      echo 'color signature green default';
      echo 'color attachment brightyellow default';
      echo 'color quoted green default';
      echo 'color quoted1 white default';
      echo 'color tilde blue default';
      echo '';
      echo '# ctrl-n, ctrl-p to select next, prev folder';
      echo '# ctrl-o to open selected folder';
      echo 'bind index \Cp sidebar-prev';
      echo 'bind index \Cn sidebar-next';
      echo 'bind index \Co sidebar-open';
      echo 'bind pager \Cp sidebar-prev';
      echo 'bind pager \Cn sidebar-next';
      echo 'bind pager \Co sidebar-open';
      echo '';
      echo '# ctrl-b toggles sidebar visibility';
      echo "macro index,pager \\Cb '<enter-command>toggle sidebar_visible<enter><redraw-screen>' 'toggle sidebar'";
      echo '';
      echo '# esc-m Mark new messages as read';
      echo 'macro index <esc>m "T~N<enter>;WNT~O<enter>;WO\CT~T<enter>" "mark all messages read"';
      echo '';
      echo '# Collapsing threads';
      echo 'macro index [ "<collapse-thread>" "collapse/uncollapse thread"';
      echo 'macro index ] "<collapse-all>"    "collapse/uncollapse all threads"';
      echo '';
      echo '# threads containing new messages';
      echo 'uncolor index "~(~N)"';
      echo 'color index brightblue default "~(~N)"';
      echo '';
      echo '# new messages themselves';
      echo 'uncolor index "~N"';
      echo 'color index brightyellow default "~N"';
      echo '';
      echo '# GPG/PGP integration';
      echo '# this set the number of seconds to keep in memory the passphrase used to encrypt/sign';
      echo 'set pgp_timeout=1800';
      echo '';
      echo '# automatically sign and encrypt with PGP/MIME';
      echo 'set pgp_autosign         # autosign all outgoing mails';
      echo 'set pgp_autoencrypt      # Try to encrypt automatically';
      echo 'set pgp_replyencrypt     # autocrypt replies to crypted';
      echo 'set pgp_replysign        # autosign replies to signed';
      echo 'set pgp_auto_decode=yes  # decode attachments';
      echo 'set fcc_clear=no         # Keep encrypted copy of sent encrypted mail';
      echo 'unset smime_is_default';
      echo '';
      echo 'set alias_file=~/.mutt-alias';
      echo 'source ~/.mutt-alias';
      echo 'set query_command= "abook --mutt-query \"%s\""';
      echo 'macro index,pager A "<pipe-message>abook --add-email-quiet<return>" "add the sender address to abook"';
      echo '';
      echo '# Optional relay of SMTP via ISP';
      echo '#set smtp_url="smtps://username:password@isp_mail_domain:465/"'; } > /etc/Muttrc

    if [[ "$ONION_ONLY" != 'no' ]]; then
        # On onion only systems email is onion router anyway, with its
        # own encryption system, so we don't need the additional pgp layer
        # except perhaps for some additional confidence
        sed -i 's|set pgp_autoencrypt|unset pgp_autoencrypt|g' /etc/Muttrc
        sed -i 's|set pgp_autosign|unset pgp_autosign|g' /etc/Muttrc
    fi

    # For viewing long URLs
    echo 'REGEXP (((http|https|ftp|gopher)|mailto)[.:][^ >"\t]*|www\.[-a-z0-9.]+)[^ .,;\t>">\):]' > "/home/$MY_USERNAME/.urlview"
    echo 'COMMAND lynx -dump -width=78 -nolist %s' >> "/home/$MY_USERNAME/.urlview"

    cp -f /etc/Muttrc "/home/$MY_USERNAME/.muttrc"
    cp -f /etc/Muttrc /etc/skel/.muttrc
    cp -f "/home/$MY_USERNAME/.urlview" /etc/skel/.urlview
    touch "/home/$MY_USERNAME/.mutt-alias"
    cp "/home/$MY_USERNAME/.mutt-alias" /etc/skel/.mutt-alias
    chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/.muttrc"
    chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/.mutt-alias"

    # default user on generic images
    if [ -d "/home/${GENERIC_IMAGE_USERNAME}" ]; then
        cp -f /etc/Muttrc "/home/${GENERIC_IMAGE_USERNAME}/.muttrc"
        chown "${GENERIC_IMAGE_USERNAME}":"${GENERIC_IMAGE_USERNAME}" "/home/${GENERIC_IMAGE_USERNAME}/.muttrc"
        touch "/home/${GENERIC_IMAGE_USERNAME}/.mutt-alias"
        chown "${GENERIC_IMAGE_USERNAME}":"${GENERIC_IMAGE_USERNAME}" "/home/${GENERIC_IMAGE_USERNAME}/.mutt-alias"
    fi

    mark_completed "${FUNCNAME[0]}"
}

function email_archiving {
    if [ ! -d /etc/exim4 ]; then
        return
    fi

    # ensure that the mail archive script is up to date
    if [ -f "/usr/local/bin/${PROJECT_NAME}-archive-mail" ]; then
        if [ ! -f /etc/cron.daily/archivemail ]; then
            cp "/usr/local/bin/${PROJECT_NAME}-archive-mail" /etc/cron.daily/archivemail
            chmod +x /etc/cron.daily/archivemail
        else
            HASH1=$(sha256sum "/usr/local/bin/${PROJECT_NAME}-archive-mail" | awk -F ' ' '{print $1}')
            HASH2=$(sha256sum /etc/cron.daily/archivemail | awk -F ' ' '{print $1}')
            if [[ "$HASH1" != "$HASH2" ]]; then
                cp "/usr/local/bin/${PROJECT_NAME}-archive-mail" /etc/cron.daily/archivemail
                chmod +x /etc/cron.daily/archivemail
            fi
        fi
    else
        if [ -f "/usr/bin/${PROJECT_NAME}-archive-mail" ]; then
            if [ ! -f /etc/cron.daily/archivemail ]; then
                cp "/usr/bin/${PROJECT_NAME}-archive-mail" /etc/cron.daily/archivemail
                chmod +x /etc/cron.daily/archivemail
            else
                HASH1=$(sha256sum "/usr/local/bin/${PROJECT_NAME}-archive-mail" | awk -F ' ' '{print $1}')
                HASH2=$(sha256sum /etc/cron.daily/archivemail | awk -F ' ' '{print $1}')
                if [[ "$HASH1" != "$HASH2" ]]; then
                    cp "/usr/local/bin/${PROJECT_NAME}-archive-mail" /etc/cron.daily/archivemail
                    chmod +x /etc/cron.daily/archivemail
                fi
            fi
        else
            echo "/usr/bin/${PROJECT_NAME}-archive-mail was not found. ${PROJECT_NAME} might not have fully installed."
            exit 62379
        fi
    fi

    # update to the next commit
    function_check set_repo_commit
    set_repo_commit "$INSTALL_DIR/cleanup-maildir" "cleanup-maildir commit" "$CLEANUP_MAILDIR_COMMIT" "$CLEANUP_MAILDIR_REPO"

    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi

    if [ ! -d "$INSTALL_DIR" ]; then
        mkdir "$INSTALL_DIR"
    fi
    cd "$INSTALL_DIR" || exit 246824245242
    function_check git_clone
    git_clone "$CLEANUP_MAILDIR_REPO" "$INSTALL_DIR/cleanup-maildir"
    cd "$INSTALL_DIR/cleanup-maildir" || exit 6887242572
    git checkout $CLEANUP_MAILDIR_COMMIT -b $CLEANUP_MAILDIR_COMMIT
    set_completion_param "cleanup-maildir commit" "$CLEANUP_MAILDIR_COMMIT"

    if [ ! -f /usr/bin/cleanup-maildir ]; then
        cp "$INSTALL_DIR/cleanup-maildir/cleanup-maildir" /usr/bin
    else
        HASH1=$(sha256sum "$INSTALL_DIR/cleanup-maildir/cleanup-maildir" | awk -F ' ' '{print $1}')
        HASH2=$(sha256sum /usr/bin/cleanup-maildir | awk -F ' ' '{print $1}')
        if [[ "$HASH1" != "$HASH2" ]]; then
            cp "$INSTALL_DIR/cleanup-maildir/cleanup-maildir" /usr/bin
        fi
    fi

    mark_completed "${FUNCNAME[0]}"
}

# Ensure that the from field is correct when sending email from Mutt
function email_from_address {
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi

    if [ ! -f "/home/$MY_USERNAME/.muttrc" ]; then
        return
    fi
    if grep -q "set from=" "/home/$MY_USERNAME/.muttrc"; then
        sed -i "s|set from=.*|set from='$MY_NAME <$MY_EMAIL_ADDRESS>'|g" "/home/$MY_USERNAME/.muttrc"
    else
        echo "set from='$MY_NAME <$MY_EMAIL_ADDRESS>'" >> "/home/$MY_USERNAME/.muttrc"
    fi

    mark_completed "${FUNCNAME[0]}"
}

function create_public_mailing_list {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    if [ ! "$PUBLIC_MAILING_LIST" ]; then
        return
    fi
    # does the mailing list have a separate domain name?
    if [ ! "$PUBLIC_MAILING_LIST_DOMAIN_NAME" ]; then
        PUBLIC_MAILING_LIST_DOMAIN_NAME="$DEFAULT_DOMAIN_NAME"
    fi

    PUBLIC_MAILING_LIST_USER="mlmmj"

    apt-get -yq install mlmmj
    adduser --system "$PUBLIC_MAILING_LIST_USER"
    addgroup "$PUBLIC_MAILING_LIST_USER"
    adduser "$PUBLIC_MAILING_LIST_USER" "$PUBLIC_MAILING_LIST_USER"

    echo ''
    echo $"Creating the $PUBLIC_MAILING_LIST mailing list"
    echo ''

    # create the list
    mlmmj-make-ml -a -L "$PUBLIC_MAILING_LIST" -c "$PUBLIC_MAILING_LIST_USER"

    { echo 'SYSTEM_ALIASES_PIPE_TRANSPORT = address_pipe';
      echo "SYSTEM_ALIASES_USER = $PUBLIC_MAILING_LIST_USER";
      echo "SYSTEM_ALIASES_GROUP = $PUBLIC_MAILING_LIST_USER"; } > /etc/exim4/conf.d/main/000_localmacros

    # router
    { echo 'mlmmj_router:';
      echo "  debug_print = \"R: mlmmj_router for \$local_part@\$domain\"";
      echo '  driver = accept';
      echo '  domains = +mlmmj_domains';
      echo "  #require_files = MLMMJ_HOME/\${lc::\$local_part}";
      echo '  # Use this instead, if you dont want to give Exim rx rights to mlmmj spool.';
      echo '  # Exim will then spawn a new process running under the UID of "mlmmj".';
      echo "  require_files = mlmmj:MLMMJ_HOME/\${lc::\$local_part}";
      echo '  local_part_suffix = +*';
      echo '  local_part_suffix_optional';
      echo '  headers_remove = Delivered-To';
      echo "  headers_add = Delivered-To: \$local_part\$local_part_suffix@\$domain";
      echo '  transport = mlmmj_transport'; } > /etc/exim4/conf.d/router/750_exim4-config_mlmmj

    # transport
    { echo 'mlmmj_transport:';
      echo "  debug_print = \"T: mlmmj_transport for \$local_part@\$domain\"";
      echo '  driver = pipe';
      echo '  return_path_add';
      echo '  user = mlmmj';
      echo '  group = mlmmj';
      echo '  home_directory = MLMMJ_HOME';
      echo '  current_directory = MLMMJ_HOME';
      echo "  command = /usr/bin/mlmmj-receive -F -L MLMMJ_HOME/\${lc:\$local_part}"; } > /etc/exim4/conf.d/transport/40_exim4-config_mlmmj

    if ! grep -q "MLMMJ_HOME=/var/spool/mlmmj" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs; then
        sed -i '/MAIN CONFIGURATION SETTINGS/a\MLMMJ_HOME=/var/spool/mlmmj' /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
    fi
    if ! grep -q "domainlist mlmmj_domains =" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs; then
        sed -i "/MLMMJ_HOME/a\\domainlist mlmmj_domains = $PUBLIC_MAILING_LIST_DOMAIN_NAME" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
    fi


    if ! grep -q "delay_warning_condition =" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs; then
        sed -i "/domainlist mlmmj_domains =/a\\delay_warning_condition = \${if match_domain{\$domain}{+mlmmj_domains}{no}{yes}}" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
    fi
    if ! grep -q ": +mlmmj_domains" /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs; then
        sed -i 's/domainlist relay_to_domains = MAIN_RELAY_TO_DOMAINS/domainlist relay_to_domains = MAIN_RELAY_TO_DOMAINS : +mlmmj_domains/g' /etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
    fi

    if ! grep -q "! +mlmmj_domains" /etc/exim4/conf.d/router/200_exim4-config_primary; then
        sed -i 's/domains = ! +local_domains/domains = ! +mlmmj_domains : ! +local_domains/g' /etc/exim4/conf.d/router/200_exim4-config_primary
    fi
    update-exim4.conf.template -r
    update-exim4.conf
    systemctl restart exim4

    if ! grep -q $"$PUBLIC_MAILING_LIST mailing list" "/home/$MY_USERNAME/README"; then
        { echo '';
        echo '';
        echo $"$PUBLIC_MAILING_LIST mailing list";
        echo '=================================';
        echo $"To subscribe to the $PUBLIC_MAILING_LIST mailing list send a";
        echo $"cleartext email to $PUBLIC_MAILING_LIST+subscribe@$DEFAULT_DOMAIN_NAME"; } >> "/home/$MY_USERNAME/README"
        chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/README"
        chmod 600 "/home/$MY_USERNAME/README"
    fi

    "${PROJECT_NAME}-addlist" -u "$MY_USERNAME" -l "$PUBLIC_MAILING_LIST" -s "$PUBLIC_MAILING_LIST"

    mark_completed "${FUNCNAME[0]}"
}

function split_gpg_key_into_fragments {
    # split the gpg key into fragments if social key management is enabled
    if [[ "$ENABLE_SOCIAL_KEY_MANAGEMENT" == "yes" ]]; then

        if [ "$IMAGE_PASSWORD_FILE" ]; then
            if [ -f "$IMAGE_PASSWORD_FILE" ]; then
                "${PROJECT_NAME}-splitkey" -u "$MY_USERNAME" -e "$MY_EMAIL_ADDRESS" --fullname "$MY_NAME" --passwordfile "$IMAGE_PASSWORD_FILE"
                return
            fi
        fi

        echo 'Splitting GPG key. You may need to enter your passphrase.'
        "${PROJECT_NAME}-splitkey" -u "$MY_USERNAME" -e "$MY_EMAIL_ADDRESS" --fullname "$MY_NAME"
        if [ ! -d "/home/$MY_USERNAME/.gnupg_fragments" ]; then
            echo 'Yhe GPG key could not be split'
            exit 86548
        fi
    fi
}

function import_email {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    EMAIL_COMPLETE_MSG=$"
  *** ${PROJECT_NAME} mailbox installation is complete ***

      Now on your internet router forward ports
     25, 587, 465, 993 and 2222 to the ${PROJECT_NAME}
"
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        if [[ "$SYSTEM_TYPE" == "mail"* ]]; then
            function_check backup_to_friends_servers
            backup_to_friends_servers

            function_check install_tripwire
            install_tripwire

            function_check split_gpg_key_into_fragments
            split_gpg_key_into_fragments

            clear
            echo ''
            echo "$EMAIL_COMPLETE_MSG"
            if [ -d "$USB_MOUNT" ]; then
                umount "$USB_MOUNT"
                rm -rf "$USB_MOUNT"
                echo $'            You can now remove the USB drive'
            fi
            exit 0
        fi
        return
    fi
    mark_completed "${FUNCNAME[0]}"
    if [[ "$SYSTEM_TYPE" == "mail"* ]]; then
        function_check backup_to_friends_servers
        backup_to_friends_servers

        function_check install_tripwire
        install_tripwire

        function_check split_gpg_key_into_fragments
        split_gpg_key_into_fragments

        # unmount any attached usb drive
        clear
        echo ''
        echo "$EMAIL_COMPLETE_MSG"
        echo ''
        if [ -d "$USB_MOUNT" ]; then
            umount "$USB_MOUNT"
            rm -rf "$USB_MOUNT"
            echo $'            You can now remove the USB drive'
        fi
        exit 0
    fi
}

function remove_email {
    echo ''
}

function install_email_basic {
    apt-get -yq remove postfix
    apt-get -yq install exim4 sasl2-bin swaks libnet-ssleay-perl procmail

    if [ ! -d /etc/exim4 ]; then
        echo $"ERROR: Exim does not appear to have installed. $CHECK_MESSAGE"
        exit 48
    fi

    # configure for Maildir format
    sed -i 's/MAIL_DIR/#MAIL_DIR/g' /etc/login.defs
    sed -i 's|#MAIL_FILE.*|MAIL_FILE Maildir/|g' /etc/login.defs

    if ! grep -q "export MAIL" /etc/profile; then
        echo 'export MAIL=~/Maildir' >> /etc/profile
    fi

    sed -i 's|pam_mail.so standard|pam_mail.so dir=~/Maildir standard|g' /etc/pam.d/login
    sed -i 's|pam_mail.so standard noenv|pam_mail.so dir=~/Maildir standard|g' /etc/pam.d/sshd
    sed -i 's|pam_mail.so nopen|pam_mail.so dir=~/Maildir nopen|g' /etc/pam.d/su

    echo "dc_eximconfig_configtype='internet'" > /etc/exim4/update-exim4.conf.conf

    if [[ $ONION_ONLY == 'no' ]]; then
        echo "dc_other_hostnames='${DEFAULT_DOMAIN_NAME};mail.${DEFAULT_DOMAIN_NAME}'" >> /etc/exim4/update-exim4.conf.conf
    else
        echo "dc_other_hostnames='${onion_address}'" >> /etc/exim4/update-exim4.conf.conf
    fi

    { echo "dc_local_interfaces=''";
      echo "dc_readhost=''";
      echo "dc_relay_domains=''";
      echo "dc_minimaldns='false'"; } >> /etc/exim4/update-exim4.conf.conf
    IPv4_address=$(get_ipv4_address)
    IPv4_address_base=$(echo "$IPv4_address" | awk -F '.' '{print $1"."$2"."$3}')
    RELAY_NETS="${IPv4_address_base}.0/24"
    if [ "$LOCAL_NETWORK_STATIC_IP_ADDRESS" ]; then
        RELAY_NETS=$(awk "$LOCAL_NETWORK_STATIC_IP_ADDRESS" -F '.' '{print $1 "." $2 "." $3 ".0/24"}')
    fi
    { echo "dc_relay_nets='$RELAY_NETS'";
      echo "dc_smarthost=''";
      echo "CFILEMODE='644'";
      echo "dc_use_split_config='false'";
      echo "dc_hide_mailname=''";
      echo "dc_mailname_in_oh='true'";
      echo "dc_localdelivery='maildir_home'";
      echo "dc_main_log_selector=-all"; } >> /etc/exim4/update-exim4.conf.conf

    echo "chunking_advertise_hosts =" > /etc/exim4/conf.d/main/04_exim4-config_chunking

    update-exim4.conf
    sed -i "s/START=no/START=yes/g" /etc/default/saslauthd
    systemctl start saslauthd

    email_install_tls

    adduser "$MY_USERNAME" sasl
    addgroup Debian-exim sasl
    systemctl restart exim4

    email_create_template

    if [ -f /usr/sbin/exim ]; then
        chmod u+s /usr/sbin/exim
    fi
    if [ -f /usr/sbin/exim4 ]; then
        chmod u+s /usr/sbin/exim4
    fi

    function_check configure_firewall_for_email
    configure_firewall_for_email
    dpkg-reconfigure --frontend noninteractive exim4-config
    systemctl restart exim4
}

function email_change_relay {
    curr_ip_address="$1"
    email_relay_base=$(echo "$curr_ip_address" | awk -F '.' '{print $1"."$2"."$3}')
    RELAY_NETS="${email_relay_base}.0/24"
    sed -i "s|dc_relay_nets=.*|dc_relay_nets='$RELAY_NETS'|g" /etc/exim4/update-exim4.conf.conf
    dpkg-reconfigure --frontend noninteractive exim4-config
}

function create_procmail {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    if [ ! -f "/home/$MY_USERNAME/.procmailrc" ]; then
        { echo "MAILDIR=\$HOME/Maildir";
          echo "DEFAULT=\$MAILDIR/";
          echo "LOGFILE=\$HOME/log/procmail.log";
          echo 'LOGABSTRACT=all';
          echo '';
          echo '# Test for an empty or missing subject line';
          echo "SUBJ_=\$(formail -xSubject: \\";
          echo "        | expand | sed -e 's/^[ ]*//g' -e 's/[ ]*\$//g')";
          echo ':0';
          echo '  * SUBJ_ ?? ^^^^';
          echo '/dev/null';
          echo '';
          echo $"# Tripwire reports which have no violations don't need to be logged";
          echo ':0 BD:'; } > "/home/$MY_USERNAME/.procmailrc"
        TRIPWIRE_VIOLATIONS_STR=$'Total violations found:  0'
        { echo "  * .*$TRIPWIRE_VIOLATIONS_STR";
          echo '/dev/null';
          echo ''; } >> "/home/$MY_USERNAME/.procmailrc"
        chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/.procmailrc"
    fi

    mkdir -p "/home/$MY_USERNAME/Maildir/admin/new"
    mkdir -p "/home/$MY_USERNAME/Maildir/admin/cur"
    chown -R "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/Maildir/admin"

    if [ ! -f /etc/skel/.procmailrc ]; then
        cp "/home/$MY_USERNAME/.procmailrc" /etc/skel/.procmailrc
        chown root:root /etc/skel/.procmailrc
    fi

    if [ -f /usr/bin/procmail ]; then
        chmod 6755 /usr/bin/procmail
    fi

    mark_completed "${FUNCNAME[0]}"
}

function handle_admin_emails {
    # keep emails for root in a separate folder
    if [ -d "/home/$MY_USERNAME/Maildir/admin" ]; then
        return
    fi

    "${PROJECT_NAME}-addemail" -u "$MY_USERNAME" -e "root@$DEFAULT_DOMAIN_NAME" -g admin --public no
}

function spam_filtering {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    apt-get -yq install exim4-daemon-heavy
    apt-get -yq install spamassassin
    if [ ! -f /etc/default/spamassassin ]; then
        echo 'Spamassassin was not installed'
        exit 72570
    fi
    sa-update -v
    sed -i 's/ENABLED=0/ENABLED=1/g' /etc/default/spamassassin
    sed -i 's/# spamd_address = 127.0.0.1 783/spamd_address = 127.0.0.1 783/g' /etc/exim4/exim4.conf.template
    # This configuration is based on https://wiki.debian.org/DebianSpamAssassin
    sed -i 's/local_parts = postmaster/local_parts = postmaster:abuse/g' /etc/exim4/conf.d/acl/30_exim4-config_check_rcpt
    sed -i '/domains = +local_domains : +relay_to_domains/a\    set acl_m0 = rfcnames' /etc/exim4/conf.d/acl/30_exim4-config_check_rcpt
    # This prevents .onion domains from being accepted
    #sed -i "s/accept/accept condition = \${if eq{\$acl_m0}{rfcnames} {1}{0}}/g" /etc/exim4/conf.d/acl/40_exim4-config_check_data

    { echo "warn  message = X-Spam-Score: \$spam_score (\$spam_bar)";
      echo '      spam = nobody:true';
      echo 'warn  message = X-Spam-Flag: YES';
      echo '      spam = nobody';
      echo "warn  message = X-Spam-Report: \$spam_report";
      echo '      spam = nobody';
      echo '# reject spam at high scores (> 12)';
      echo "deny  message = This message scored \$spam_score spam points.";
      echo '      spam = nobody:true';
      echo "      condition = \${if >{\$spam_score_int}{120}{1}{0}}"; } >> /etc/exim4/conf.d/acl/40_exim4-config_check_data
    # procmail configuration
    { echo '# get spamassassin to check emails';
      echo ':0fw: .spamassassin.lock';
      echo '  * < 256000';
      echo '| spamc';
      echo '# strong spam are discarded';
      echo ':0';
      echo '  * ^X-Spam-Level: \*\*\*\*\*\*';
      echo '/dev/null';
      echo '# weak spam are kept just in case - clear this out every now and then';
      echo ':0';
      echo '  * ^X-Spam-Level: \*\*\*\*\*';
      echo 'maybe-spam/';
      echo '# otherwise, marginal spam goes here for revision';
      echo ':0';
      echo '  * ^X-Spam-Level: \*\*';
      echo 'spam/'; } >> "/home/$MY_USERNAME/.procmailrc"
    chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/.procmailrc"
    { echo '# get spamassassin to check emails';
      echo ':0fw: .spamassassin.lock';
      echo '  * < 256000';
      echo '| spamc';
      echo '# strong spam are discarded';
      echo ':0';
      echo '  * ^X-Spam-Level: \*\*\*\*\*\*';
      echo '/dev/null';
      echo '# weak spam are kept just in case - clear this out every now and then';
      echo ':0';
      echo '  * ^X-Spam-Level: \*\*\*\*\*';
      echo 'maybe-spam/';
      echo '# otherwise, marginal spam goes here for revision';
      echo ':0';
      echo '  * ^X-Spam-Level: \*\*';
      echo 'spam/'; } >> /etc/skel/.procmailrc
    # filtering scripts
    { echo '#!/bin/bash';
      echo 'for d in /home/*/ ; do';
      echo "    USERNAME=\$(echo \"\$d\" | awk -F '/' '{print \$3}')";
      echo "    if [[ \$USERNAME != \"git\" && $USERNAME != \"go\" && \$USERNAME != \"gogs\" && \$USERNAME != \"sync\" && \$USERNAME != \"tahoelafs\" ]]; then";
      echo "        MAILDIR=/home/\$USERNAME/Maildir/.learn-spam";
      echo "        if [ ! -d \"\$MAILDIR\" ]; then";
      echo '           exit';
      echo '        fi';
      echo "        for f in \$(ls \$MAILDIR/cur)";
      echo '        do';
      echo "            spamc -L spam < \"\$MAILDIR/cur/\$f\" > /dev/null";
      echo "            rm \"\$MAILDIR/cur/\$f\"";
      echo '        done';
      echo "        for f in \$(ls \$MAILDIR/new)";
      echo '        do';
      echo "            spamc -L spam < \"\$MAILDIR/new/\$f\" > /dev/null";
      echo "            rm \"\$MAILDIR/new/\$f\"";
      echo '        done';
      echo '    fi';
      echo 'done';
      echo 'exit 0'; } > /usr/bin/filterspam

    { echo '#!/bin/bash';
      echo 'for d in /home/*/ ; do';
      echo "    USERNAME=\$(echo \"\$d\" | awk -F '/' '{print \$3}')";
      echo "    if [[ \$USERNAME != \"git\" && \$USERNAME != \"go\" && \$USERNAME != \"gogs\" && \$USERNAME != \"sync\" && \$USERNAME != \"tahoelafs\" ]]; then";
      echo "        MAILDIR=/home/\$USERNAME/Maildir/.learn-ham";
      echo "        if [ ! -d \"\$MAILDIR\" ]; then";
      echo '            exit';
      echo '        fi';
      echo "        for f in \$(ls \$MAILDIR/cur)";
      echo '        do';
      echo "            spamc -L ham < \"\$MAILDIR/cur/\$f\" > /dev/null";
      echo "            rm \"\$MAILDIR/cur/\$f\"";
      echo '        done';
      echo "        for f in \$(ls \$MAILDIR/new)";
      echo '        do';
      echo "            spamc -L ham < \"\$MAILDIR/new/\$f\" > /dev/null";
      echo "            rm \"\$MAILDIR/new/\$f\"";
      echo '        done';
      echo '    fi';
      echo 'done';
      echo 'exit 0'; } > /usr/bin/filterham

    function_check cron_add_mins
    cron_add_mins 3 '/usr/bin/timeout 120 /usr/bin/filterspam'
    cron_add_mins 3 '/usr/bin/timeout 120 /usr/bin/filterham'
    chmod 655 /usr/bin/filterspam /usr/bin/filterham
    sed -i 's/# use_bayes 1/use_bayes 1/g' /etc/mail/spamassassin/local.cf
    sed -i 's/# bayes_auto_learn 1/bayes_auto_learn 1/g' /etc/mail/spamassassin/local.cf

    # user preferences
    if [ ! -d "/home/$MY_USERNAME/.spamassassin" ]; then
        mkdir "/home/$MY_USERNAME/.spamassassin"
        { echo $'# How many points before a mail is considered spam.';
          echo '# required_score        5';
          echo '';
          echo $'# Whitelist and blacklist addresses are now file-glob-style patterns, so';
          echo $'# "friend@somewhere.com", "*@isp.com", or "*.domain.net" will all work.';
          echo '# whitelist_from    someone@somewhere.com';
          echo '';
          echo $'# Add your own customised scores for some tests below.  The default scores are';
          echo $'# read from the installed spamassassin rules files, but you can override them';
          echo $'# here.  To see the list of tests and their default scores, go to';
          echo '# http://spamassassin.apache.org/tests.html .';
          echo '#';
          echo '# score SYMBOLIC_TEST_NAME n.nn';
          echo '';
          echo $'# Speakers of Asian languages, like Chinese, Japanese and Korean, will almost';
          echo $'# definitely want to uncomment the following lines.  They will switch off some';
          echo $'# rules that detect 8-bit characters, which commonly trigger on mails using CJK';
          echo $'# character sets, or that assume a western-style charset is in use. ';
          echo '# ';
          echo '# score HTML_COMMENT_8BITS  0';
          echo '# score UPPERCASE_25_50     0';
          echo '# score UPPERCASE_50_75     0';
          echo '# score UPPERCASE_75_100    0';
          echo '# score OBSCURED_EMAIL      0';
          echo '';
          echo $'# Speakers of any language that uses non-English, accented characters may wish';
          echo $'# to uncomment the following lines.   They turn off rules that fire on';
          echo $'# misformatted messages generated by common mail apps in contravention of the';
          echo $'# email RFCs.';
          echo '';
          echo '# score SUBJ_ILLEGAL_CHARS      0'; } > "/home/$MY_USERNAME/.spamassassin/user_prefs"
    fi
    # this must be accessible by root
    chown -R "$MY_USERNAME":root "/home/$MY_USERNAME/.spamassassin"

    # script to keep spamassassin running
    # There is a systemd script from the debian package, but it doesn't restart on failure
    # and also doesn't ensure start after networking is up. If that is eventually fixed
    # then this script and the cron job which runs it can be removed.
    script_name=/usr/bin/run-spamassassin
    { echo '#!/bin/bash';
      echo "current_state=\$(systemctl status spamassassin)";
      echo "if [[ \"\$current_state\" != *\"(running)\"* ]]; then";
      echo '    systemctl restart spamassassin';
      echo 'fi';
      echo 'exit 0'; } > $script_name
    chmod +x $script_name

    systemctl start spamassassin
    systemctl restart exim4
    systemctl restart cron
    function_check cron_add_mins
    cron_add_mins 10 "$script_name 2> /dev/null"

    mark_completed "${FUNCNAME[0]}"
}

function configure_imap {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi

    apt-get -yq install dovecot-imapd

    if [ ! -d /etc/dovecot ]; then
        echo $"ERROR: Dovecot does not appear to have installed. $CHECK_MESSAGE"
        exit 48
    fi

    if [[ "$(cert_exists dovecot)" == "0" ]]; then
        "${PROJECT_NAME}-addcert" -h dovecot --dhkey "$DH_KEYLENGTH"
        CHECK_HOSTNAME=dovecot
        check_certificates dovecot
    fi

    chmod 600 /etc/shadow
    chmod 600 /etc/gshadow
    groupadd default
    usermod -g default dovecot
    chmod 0000 /etc/shadow
    chmod 0000 /etc/gshadow

    chown root:default /etc/ssl/certs/dovecot.*
    chown root:default /etc/ssl/private/dovecot.*
    chown root:default "/etc/ssl/certs/${DEFAULT_DOMAIN_NAME}.*"
    chown root:default "/etc/ssl/private/${DEFAULT_DOMAIN_NAME}.*"

    if [ ! -f /etc/dovecot/conf.d/10-ssl.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-ssl.conf'
        exit 83629
    fi
    sed -i 's|#ssl =.*|ssl = no|g' /etc/dovecot/conf.d/10-ssl.conf
    sed -i 's|ssl =.*|ssl = no|g' /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|#ssl_cert =.*|ssl_cert = </etc/ssl/certs/dovecot.crt|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|ssl_cert =.*|ssl_cert = </etc/ssl/certs/dovecot.crt|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|#ssl_key =.*|ssl_key = </etc/ssl/private/dovecot.key|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|ssl_key =.*|ssl_key = </etc/ssl/private/dovecot.key|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|#ssl_dh_parameters_length.*|ssl_dh_parameters_length = ${DH_KEYLENGTH}|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i 's/#ssl_prefer_server_ciphers.*/ssl_prefer_server_ciphers = yes/g' /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|#ssl_protocols =.*|ssl_protocols = '$SSL_PROTOCOLS'|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i "s|ssl_protocols =.*|ssl_protocols = '$SSL_PROTOCOLS'|g" /etc/dovecot/conf.d/10-ssl.conf
    echo "ssl_cipher_list = '$SSL_CIPHERS'" >> /etc/dovecot/conf.d/10-ssl.conf

    if [ ! -f /etc/dovecot/conf.d/10-master.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-master.conf'
        exit 49259
    fi
    sed -i 's/#process_limit =.*/process_limit = 100/g' /etc/dovecot/conf.d/10-master.conf

    if [ ! -f /etc/dovecot/conf.d/10-logging.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-logging.conf'
        exit 48936
    fi
    sed -i 's/#auth_verbose.*/auth_verbose = yes/g' /etc/dovecot/conf.d/10-logging.conf

    if [ ! -f /etc/dovecot/dovecot.conf ]; then
        echo $'Unable to find /etc/dovecot/dovecot.conf'
        exit 43890
    fi
    sed -i 's/#listen =.*/listen = */g' /etc/dovecot/dovecot.conf

    if [ ! -f /etc/dovecot/conf.d/10-auth.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-auth.conf'
        exit 843256
    fi
    sed -i 's/#disable_plaintext_auth =.*/disable_plaintext_auth = no/g' /etc/dovecot/conf.d/10-auth.conf
    sed -i 's/auth_mechanisms =.*/auth_mechanisms = plain login/g' /etc/dovecot/conf.d/10-auth.conf

    if [ ! -f /etc/dovecot/conf.d/10-mail.conf ]; then
        echo $'Unable to find /etc/dovecot/conf.d/10-mail.conf'
        exit 42036
    fi
    sed -i 's|mail_location =.*|mail_location = maildir:~/Maildir:LAYOUT=fs|g' /etc/dovecot/conf.d/10-mail.conf

    # This long notify interval makes the system more suited for use with
    # battery powered mobile devices
    sed -i 's|#imap_idle_notify_interval =.*|imap_idle_notify_interval = 29|g' /etc/dovecot/conf.d/20-imap.conf

    if [ -f /var/lib/dovecot/ssl-parameters.dat ]; then
        rm /var/lib/dovecot/ssl-parameters.dat
    fi

    if [ -f /etc/systemd/system/sockets.target.wants/dovecot.socket ]; then
        rm /etc/systemd/system/sockets.target.wants/dovecot.socket
    fi

    # Separate logging, otherwise syslog is used
    if ! grep -q "# logging" /etc/dovecot/dovecot.conf; then
        { echo '';
          echo '# logging';
          echo 'log_path = /var/log/dovecot.log';
          echo 'info_log_path = /var/log/dovecot-info.log';
          echo 'debug_log_path = /var/log/dovecot-debug.log'; } >> /etc/dovecot/dovecot.conf
    fi

    systemctl restart dovecot
    mark_completed "${FUNCNAME[0]}"
}

function configure_imap_client_certs {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    # http://strange.systems/certificate-based-auth-with-dovecot-sendmail/
    sed -i 's|#default_process_limit =.*|default_process_limit = 100|g' /etc/dovecot/conf.d/10-master.conf
    sed -i 's/disable_plaintext_auth =.*/disable_plaintext_auth = yes/g' /etc/dovecot/conf.d/10-auth.conf
    sed -i 's|#auth_ssl_require_client_cert =.*|auth_ssl_require_client_cert = yes|g' /etc/dovecot/conf.d/10-auth.conf
    sed -i 's|#auth_ssl_username_from_cert =.*|auth_ssl_username_from_cert = yes|g' /etc/dovecot/conf.d/10-auth.conf
    sed -i "s|#ssl_ca =.*|ssl_ca = /etc/ssl/certs/ca-$DEFAULT_DOMAIN_NAME.crt|g" /etc/dovecot/conf.d/10-ssl.conf
    sed -i 's|#ssl_cert_username_field =.*|ssl_cert_username_field = commonName|g' /etc/dovecot/conf.d/10-ssl.conf
    sed -i 's|#ssl_verify_client_cert =.*|ssl_verify_client_cert = yes|g' /etc/dovecot/conf.d/10-ssl.conf
    if ! grep -q "passdb {" /etc/dovecot/conf.d/10-auth.conf; then
        { echo '';
          echo 'passdb {';
          echo '  driver = passwd-file';
          echo '  args = /etc/dovecot/passwd-file';
          echo '  deny = no';
          echo '  master = no';
          echo '  pass = no';
          echo '}'; } >> /etc/dovecot/conf.d/10-auth.conf
    fi
    if [[ "$ONION_ONLY" == "no" ]]; then
        # make a CA cert
        if [ ! -f "/etc/ssl/private/ca-$DEFAULT_DOMAIN_NAME.key" ]; then
            if [[ "$LETSENCRYPT_ENABLED" != "yes" ]]; then
                "${PROJECT_NAME}-addcert" -h "$DEFAULT_DOMAIN_NAME" --ca "" --dhkey "$DH_KEYLENGTH"
            else
                "${PROJECT_NAME}-addcert" -e "$DEFAULT_DOMAIN_NAME" -s "$LETSENCRYPT_SERVER" --ca "" --dhkey "$DH_KEYLENGTH" --email "$MY_EMAIL_ADDRESS"
            fi
        fi
    fi
    # CA configuration
    { echo '[ ca ]';
      echo "default_ca = dovecot-ca";
      echo '';
      echo '[ crl_ext ]';
      echo 'authorityKeyIdentifier=keyid:always';
      echo '';
      echo '[ dovecot-ca ]';
      echo 'new_certs_dir = .';
      echo 'unique_subject = no';
      echo "certificate = /etc/ssl/certs/ca-$DEFAULT_DOMAIN_NAME.crt";
      echo 'database = ssldb';
      echo "private_key = /etc/ssl/private/ca-$DEFAULT_DOMAIN_NAME.key";
      echo 'serial = sslserial';
      echo 'default_days = 3650';
      echo 'default_md = sha256';
      echo 'default_bits = 2048';
      echo 'policy = dovecot-ca_policy';
      echo 'x509_extensions = dovecot-ca_extensions';
      echo '';
      echo '[ dovecot-ca_policy ]';
      echo 'commonName = supplied';
      echo 'stateOrProvinceName = supplied';
      echo 'countryName = supplied';
      echo 'emailAddress = optional';
      echo 'organizationName = supplied';
      echo 'organizationalUnitName = optional';
      echo '';
      echo '[ dovecot-ca_extensions ]';
      echo 'basicConstraints = CA:false';
      echo 'subjectKeyIdentifier = hash';
      echo 'authorityKeyIdentifier = keyid:always';
      echo 'keyUsage = digitalSignature,keyEncipherment';
      echo 'extendedKeyUsage = clientAuth'; } > /etc/ssl/dovecot-ca.cnf
    if [ -f /etc/ssl/ssldb ]; then
        rm /etc/ssl/ssldb
    fi
    if [ -f /etc/ssl/sslserial ]; then
        rm /etc/ssl/sslserial
    fi
    touch /etc/ssl/ssldb
    echo 0001 > /etc/ssl/sslserial
    #${PROJECT_NAME}-clientcert -u $MY_USERNAME
    systemctl restart dovecot
    mark_completed "${FUNCNAME[0]}"
}

function create_gpg_subkey {
    # Note: currently not used
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    apt-get -yq install gnupg

    GPG_KEY_USAGE=$1
    if [[ "$GPG_KEY_USAGE" != "sign" && "$GPG_KEY_USAGE" != "auth" && "$GPG_KEY_USAGE" != "encrypt" ]]; then
        echo $"Unknown subkey usage: $GPG_KEY_USAGE"
        echo $'Available types: sign|auth|encrypt'
        exit 14783
    fi

    KEYGRIP=$(gpg --fingerprint --fingerprint "$MY_EMAIL_ADDRESS" | grep fingerprint | tail -1 | cut -d= -f2 | sed -e 's/ //g')

    # Generate a GPG subkey
    { echo 'Key-Type: eddsa';
      echo 'Key-Curve: Ed25519';
      echo "Key-Grip: $KEYGRIP";
      echo 'Subkey-Type: eddsa';
      echo "subkey-Usage: $GPG_KEY_USAGE";
      echo "Name-Real:  $MY_NAME";
      echo "Name-Email: $MY_EMAIL_ADDRESS";
      echo "Name-Comment: $GPG_KEY_USAGE";
      echo 'Expire-Date: 0';
      echo "Passphrase: $PROJECT_NAME"; } > "/home/$MY_USERNAME/gpg-genkey.conf"
    chown "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/gpg-genkey.conf"
    su -m root -c "gpg --homedir /home/$MY_USERNAME/.gnupg --batch --full-gen-key /home/$MY_USERNAME/gpg-genkey.conf" - "$MY_USERNAME"
    chown -R "$MY_USERNAME":"$MY_USERNAME" "/home/$MY_USERNAME/.gnupg"

    shred -zu "/home/$MY_USERNAME/gpg-genkey.conf"

    # shellcheck disable=SC2034
    MY_GPG_SUBKEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")

    mark_completed "${FUNCNAME[0]}"
}

function gpg_key_exists {
    key_owner_username="$1"
    key_search_text="$2"
    if [[ $key_owner_username != "root" ]]; then
        KEY_EXISTS=$(su -c "gpg --list-keys \"${key_search_text}\"" - "$key_owner_username")
    else
        KEY_EXISTS=$(gpg --list-keys "${key_search_text}")
    fi
    if [ ! "$KEY_EXISTS" ]; then
        echo "no"
        return
    fi
    if [[ "$KEY_EXISTS" == *"error"* ]]; then
        echo "no"
        return
    fi
    echo "yes"
}

function configure_gpg {
    if [ ! -d /etc/exim4 ]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi
    apt-get -yq install gnupg dirmngr
    printf '%%Assuan%%\nsocket=/dev/shm/S.dirmngr\n' > ~/.gnupg/S.dirmngr

    check_email_address_exists

    gpg_dir="/home/$MY_USERNAME/.gnupg"

    # if gpg keys directory was previously imported from usb
    if [ -d "$gpg_dir" ]; then
        echo $'GPG directory exists'
    else
        echo $"GPG directory $gpg_dir was not found"
    fi
    if [ -d "$gpg_dir" ]; then
        echo $'GPG keys were imported'
        sed -i "s|keyserver hkp://keys.gnupg.net|keyserver $GPG_KEYSERVER|g" "$gpg_dir/gpg.conf"
        MY_GPG_PUBLIC_KEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        if [ ${#MY_GPG_PUBLIC_KEY_ID} -lt 4 ]; then
            echo $'GPG public key ID could not be obtained'
        else
            if [[ "$MY_GPG_PUBLIC_KEY_ID" == *'error'* ]]; then
                echo $"Can't locate gpg key"
            else
                chown -R "$MY_USERNAME":"$MY_USERNAME" "$gpg_dir"
                chmod 700 "$gpg_dir"
                chmod 600 "$gpg_dir/"*
                printf '%%Assuan%%\nsocket=/dev/shm/S.dirmngr\n' > "/home/$MY_USERNAME/.gnupg/S.dirmngr"
                if [ -d "/home/$MY_USERNAME/.gnupg/crls.d" ]; then
                    chmod +x "/home/$MY_USERNAME/.gnupg/crls.d"
                fi
                mark_completed "${FUNCNAME[0]}"
                return
            fi
        fi
    fi

    if [ ! -d "$gpg_dir" ]; then
        mkdir "$gpg_dir"
        echo "keyserver $GPG_KEYSERVER" >> "$gpg_dir/gpg.conf"
        echo 'keyserver-options auto-key-retrieve' >> "$gpg_dir/gpg.conf"
    fi

    sed -i "s|keyserver hkp://keys.gnupg.net|keyserver $GPG_KEYSERVER|g" "$gpg_dir/gpg.conf"

    gpg_agent_setup root
    gpg_agent_setup "$MY_USERNAME"

    if ! grep -q "# default preferences" "$gpg_dir/gpg.conf"; then
        { echo '';
          echo '# default preferences';
          echo 'personal-digest-preferences SHA256';
          echo 'cert-digest-algo SHA256';
          echo 'default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES CAST5 ZLIB BZIP2 ZIP Uncompressed'; } >> "$gpg_dir/gpg.conf"
    fi

    chown -R "$MY_USERNAME":"$MY_USERNAME" "$gpg_dir"
    chmod 700 "$gpg_dir"
    chmod 600 "$gpg_dir/"*
    printf '%%Assuan%%\nsocket=/dev/shm/S.dirmngr\n' > "$gpg_dir/S.dirmngr"
    if [ -d "$gpg_dir/crls.d" ]; then
        chmod +x "$gpg_dir/crls.d"
    fi

    if [[ "$MY_GPG_PUBLIC_KEY" && "$MY_GPG_PRIVATE_KEY" ]]; then
        echo $'Importing GPG keys from file'
        echo $"Public key:  $MY_GPG_PUBLIC_KEY"
        echo $"Private key: $MY_GPG_PRIVATE_KEY"

        # use your existing GPG keys which were exported
        if [ ! -f $MY_GPG_PUBLIC_KEY ]; then
            echo $"GPG public key file $MY_GPG_PUBLIC_KEY was not found"
            exit 2483
        fi

        if [ ! -f $MY_GPG_PRIVATE_KEY ]; then
            echo $"GPG private key file $MY_GPG_PRIVATE_KEY was not found"
            exit 5383
        fi

        gpg_import_public_key "$MY_USERNAME" "$MY_GPG_PUBLIC_KEY"
        gpg_import_private_key "$MY_USERNAME" "$MY_GPG_PRIVATE_KEY"

        KEY_EXISTS=$(gpg_key_exists "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        if [[ $KEY_EXISTS == "no" ]]; then
            echo $"The GPG key for $MY_EMAIL_ADDRESS could not be imported"
            exit 13821
        fi

        # for security ensure that the private key file doesn't linger around
        shred -zu $MY_GPG_PRIVATE_KEY
        MY_GPG_PUBLIC_KEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        if [ ${#MY_GPG_PUBLIC_KEY_ID} -lt 4 ]; then
            echo $'GPG public key ID could not be obtained'
        fi
    else
        # Generate a GPG key
        if [ -f "$IMAGE_PASSWORD_FILE" ]; then
            gpg_create_key "$MY_USERNAME" "$(printf "%s" "$(cat "$IMAGE_PASSWORD_FILE")")"
        else
            gpg_create_key "$MY_USERNAME" "$PROJECT_NAME"
        fi
        MY_GPG_PUBLIC_KEY_ID=$(gpg_pubkey_from_email "$MY_USERNAME" "$MY_EMAIL_ADDRESS")
        MY_GPG_PUBLIC_KEY=/tmp/public_key.gpg
        gpg_export_public_key "$MY_USERNAME" "$MY_GPG_PUBLIC_KEY_ID" "$MY_GPG_PUBLIC_KEY"
    fi

    if [ ! -d /root/.gnupg ]; then
        cp -r "/home/$MY_USERNAME/.gnupg" /root/
        chmod 700 /root/.gnupg
        chmod 600 /root/.gnupg/*
        printf '%%Assuan%%\nsocket=/dev/shm/S.dirmngr\n' > /root/.gnupg/S.dirmngr
        if [ -d /root/.gnupg/crls.d ]; then
            chmod +x /root/.gnupg/crls.d
        fi
    fi

    mark_completed "${FUNCNAME[0]}"
}

function refresh_gpg_keys {
    REFRESH_GPG_KEYS_SCRIPT=/tmp/update-gpg-keys
    { echo '#!/bin/bash';
      echo "if [ -f /usr/local/bin/${PROJECT_NAME}-sec ]; then";
      echo "    /usr/bin/timeout 600 /usr/local/bin/${PROJECT_NAME}-sec --refresh yes";
      echo 'else';
      echo "    /usr/bin/timeout 600 /usr/bin/${PROJECT_NAME}-sec --refresh yes";
      echo 'fi';
      echo 'exit 0'; } > "$REFRESH_GPG_KEYS_SCRIPT"
    chmod +x "$REFRESH_GPG_KEYS_SCRIPT"

    if [ ! -f /usr/bin/update-gpg-keys ]; then
        cp "$REFRESH_GPG_KEYS_SCRIPT" /usr/bin/update-gpg-keys
    else
        HASH1=$(sha256sum "$REFRESH_GPG_KEYS_SCRIPT" | awk -F ' ' '{print $1}')
        HASH2=$(sha256sum /usr/bin/update-gpg-keys | awk -F ' ' '{print $1}')
        if [[ "$HASH1" != "$HASH2" ]]; then
            cp $REFRESH_GPG_KEYS_SCRIPT /usr/bin/update-gpg-keys
        fi
        rm $REFRESH_GPG_KEYS_SCRIPT
    fi

    REFRESH_GPG_KEYS_SCRIPT=/usr/bin/update-gpg-keys
    if grep -q "${PROJECT_NAME}-sec" /etc/crontab; then
        sed -i "/${PROJECT_NAME}-sec /d" /etc/crontab
    fi
    if ! grep -q "$REFRESH_GPG_KEYS_SCRIPT" /etc/crontab; then
        GPG_REFRESH_TIME=$(( RANDOM % 60 ))
        echo "$GPG_REFRESH_TIME            */$REFRESH_GPG_KEYS_HOURS *   *   *   root cronic $REFRESH_GPG_KEYS_SCRIPT" >> /etc/crontab
        systemctl restart cron
    else
        if ! grep "root cronic $REFRESH_GPG_KEYS_SCRIPT" /etc/crontab; then
            sed -i "s|root $REFRESH_GPG_KEYS_SCRIPT.*|root cronic $REFRESH_GPG_KEYS_SCRIPT|g" /etc/crontab
        fi
    fi
}

function install_email {
    if [[ $SYSTEM_TYPE == "mesh"* ]]; then
        return
    fi
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi

    create_email_onion_address
    check_email_address_exists
    install_email_basic
    configure_email_onion

    mark_completed "${FUNCNAME[0]}"
}

# NOTE: deliberately no exit 0